Comparative Theoretical Analysis of BN Nanotubes Doped with Al, P, Ga, As, In, and Sb

The electronic structure of a (5,5) boron nitride nanotube (BN NT) doped with periodically distributed Al, P, Ga, As, In, or Sb atoms is calculated using two methods: linear combination of atomic orbitals (LCAO) realized via atomic centered Gaussian-type functions as a basis set (BS) and linearized augmented cylindrical wave (LACW) method accompanied with the local density functional and muffin-tin approximations for the electronic potential. Both methods predict with a qualitative agreement the formation of relatively stable point defects associated with the atom substitutions in the BN NT wall. Substantial atomic relaxation of defective NTs leads to the increase of covalency in the defect–B(N) bond along with extra charge redistribution between the defect and the nanotube. The calculated density of states shows narrowing of the band gap, due to formation of midgap states induced by defects.